com.webcodepro.applecommander.storage.physical.ProdosOrder Maven / Gradle / Ivy
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/*
* AppleCommander - An Apple ][ image utility.
* Copyright (C) 2003-2022 by Robert Greene
* robgreene at users.sourceforge.net
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package com.webcodepro.applecommander.storage.physical;
import com.webcodepro.applecommander.storage.Disk;
import com.webcodepro.applecommander.storage.StorageBundle;
import com.webcodepro.applecommander.util.TextBundle;
/**
* Supports disk images stored in ProDOS physical order.
*
* @author Rob Greene ([email protected])
*/
public class ProdosOrder extends ImageOrder {
private TextBundle textBundle = StorageBundle.getInstance();
/**
* This table contains the block offset for a particular DOS sector.
*/
private static final int[] blockInterleave = {
0, 7, 6, 6, 5, 5, 4, 4, 3, 3, 2, 2, 1, 1, 0, 7
};
/**
* Defines the location within a block in which the DOS sector resides.
* (0 = 0-255 and 1 = 256-511.)
*/
private static final int[] blockOffsets = {
0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1
};
/**
* Construct a ProdosOrder.
*/
public ProdosOrder(ByteArrayImageLayout diskImageManager) {
super(diskImageManager);
}
/**
* Indicates that this device is block ordered.
*/
public boolean isBlockDevice() {
return true;
}
/**
* Indicates that this device is track and sector ordered.
*/
public boolean isTrackAndSectorDevice() {
return false;
}
/**
* Read the block from the disk image.
* Note: Defined in terms of reading sectors.
*/
public byte[] readBlock(int block) {
return readBytes(block * Disk.BLOCK_SIZE, Disk.BLOCK_SIZE);
}
/**
* Write the block to the disk image.
* Note: Defined in terms of reading sectors.
*/
public void writeBlock(int block, byte[] data) {
writeBytes(block * Disk.BLOCK_SIZE, data);
}
/**
* Retrieve the specified sector.
*/
public byte[] readSector(int track, int sector) throws IllegalArgumentException {
int block = track * 8 + blockInterleave[sector];
byte[] blockData = readBlock(block);
int offset = blockOffsets[sector];
byte[] sectorData = new byte[Disk.SECTOR_SIZE];
System.arraycopy(blockData, offset * Disk.SECTOR_SIZE,
sectorData, 0, Disk.SECTOR_SIZE);
return sectorData;
}
/**
* Write the specified sector.
*/
public void writeSector(int track, int sector, byte[] bytes) throws IllegalArgumentException {
int block = track * 8 + blockInterleave[sector];
byte[] blockData = readBlock(block);
int offset = blockOffsets[sector];
System.arraycopy(bytes, 0, blockData, offset * Disk.SECTOR_SIZE, bytes.length);
writeBlock(block, blockData);
}
/**
* Return the name of this image order.
*/
public String getName() {
return textBundle.get("ProdosOrder.OrderName"); //$NON-NLS-1$
}
}